1 /* 2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/altHashing.hpp" 27 #include "classfile/compactHashtable.inline.hpp" 28 #include "classfile/javaClasses.hpp" 29 #include "classfile/symbolTable.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "gc/shared/collectedHeap.inline.hpp" 32 #include "gc/shared/gcLocker.inline.hpp" 33 #include "memory/allocation.inline.hpp" 34 #include "memory/filemap.hpp" 35 #include "memory/resourceArea.hpp" 36 #include "oops/oop.inline.hpp" 37 #include "runtime/atomic.hpp" 38 #include "runtime/mutexLocker.hpp" 39 #include "utilities/hashtable.inline.hpp" 40 41 // -------------------------------------------------------------------------- 42 // the number of buckets a thread claims 43 const int ClaimChunkSize = 32; 44 45 SymbolTable* SymbolTable::_the_table = NULL; 46 // Static arena for symbols that are not deallocated 47 Arena* SymbolTable::_arena = NULL; 48 bool SymbolTable::_needs_rehashing = false; 49 bool SymbolTable::_lookup_shared_first = false; 50 51 CompactHashtable<Symbol*, char> SymbolTable::_shared_table; 52 53 Symbol* SymbolTable::allocate_symbol(const u1* name, int len, bool c_heap, TRAPS) { 54 assert (len <= Symbol::max_length(), "should be checked by caller"); 55 56 Symbol* sym; 57 58 if (DumpSharedSpaces) { 59 // Allocate all symbols to CLD shared metaspace 60 sym = new (len, ClassLoaderData::the_null_class_loader_data(), THREAD) Symbol(name, len, PERM_REFCOUNT); 61 } else if (c_heap) { 62 // refcount starts as 1 63 sym = new (len, THREAD) Symbol(name, len, 1); 64 assert(sym != NULL, "new should call vm_exit_out_of_memory if C_HEAP is exhausted"); 65 } else { 66 // Allocate to global arena 67 sym = new (len, arena(), THREAD) Symbol(name, len, PERM_REFCOUNT); 68 } 69 return sym; 70 } 71 72 void SymbolTable::initialize_symbols(int arena_alloc_size) { 73 // Initialize the arena for global symbols, size passed in depends on CDS. 74 if (arena_alloc_size == 0) { 75 _arena = new (mtSymbol) Arena(mtSymbol); 76 } else { 77 _arena = new (mtSymbol) Arena(mtSymbol, arena_alloc_size); 78 } 79 } 80 81 // Call function for all symbols in the symbol table. 82 void SymbolTable::symbols_do(SymbolClosure *cl) { 83 // all symbols from shared table 84 _shared_table.symbols_do(cl); 85 86 // all symbols from the dynamic table 87 const int n = the_table()->table_size(); 88 for (int i = 0; i < n; i++) { 89 for (HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); 90 p != NULL; 91 p = p->next()) { 92 cl->do_symbol(p->literal_addr()); 93 } 94 } 95 } 96 97 int SymbolTable::_symbols_removed = 0; 98 int SymbolTable::_symbols_counted = 0; 99 volatile int SymbolTable::_parallel_claimed_idx = 0; 100 101 void SymbolTable::buckets_unlink(int start_idx, int end_idx, int* processed, int* removed) { 102 for (int i = start_idx; i < end_idx; ++i) { 103 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); 104 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); 105 while (entry != NULL) { 106 // Shared entries are normally at the end of the bucket and if we run into 107 // a shared entry, then there is nothing more to remove. However, if we 108 // have rehashed the table, then the shared entries are no longer at the 109 // end of the bucket. 110 if (entry->is_shared() && !use_alternate_hashcode()) { 111 break; 112 } 113 Symbol* s = entry->literal(); 114 (*processed)++; 115 assert(s != NULL, "just checking"); 116 // If reference count is zero, remove. 117 if (s->refcount() == 0) { 118 assert(!entry->is_shared(), "shared entries should be kept live"); 119 delete s; 120 (*removed)++; 121 *p = entry->next(); 122 the_table()->free_entry(entry); 123 } else { 124 p = entry->next_addr(); 125 } 126 // get next entry 127 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); 128 } 129 } 130 } 131 132 // Remove unreferenced symbols from the symbol table 133 // This is done late during GC. 134 void SymbolTable::unlink(int* processed, int* removed) { 135 size_t memory_total = 0; 136 buckets_unlink(0, the_table()->table_size(), processed, removed); 137 _symbols_removed += *removed; 138 _symbols_counted += *processed; 139 } 140 141 void SymbolTable::possibly_parallel_unlink(int* processed, int* removed) { 142 const int limit = the_table()->table_size(); 143 144 size_t memory_total = 0; 145 146 for (;;) { 147 // Grab next set of buckets to scan 148 int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize; 149 if (start_idx >= limit) { 150 // End of table 151 break; 152 } 153 154 int end_idx = MIN2(limit, start_idx + ClaimChunkSize); 155 buckets_unlink(start_idx, end_idx, processed, removed); 156 } 157 Atomic::add(*processed, &_symbols_counted); 158 Atomic::add(*removed, &_symbols_removed); 159 } 160 161 // Create a new table and using alternate hash code, populate the new table 162 // with the existing strings. Set flag to use the alternate hash code afterwards. 163 void SymbolTable::rehash_table() { 164 if (DumpSharedSpaces) { 165 tty->print_cr("Warning: rehash_table should not be called while dumping archive"); 166 return; 167 } 168 169 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 170 // This should never happen with -Xshare:dump but it might in testing mode. 171 if (DumpSharedSpaces) return; 172 // Create a new symbol table 173 SymbolTable* new_table = new SymbolTable(); 174 175 the_table()->move_to(new_table); 176 177 // Delete the table and buckets (entries are reused in new table). 178 delete _the_table; 179 // Don't check if we need rehashing until the table gets unbalanced again. 180 // Then rehash with a new global seed. 181 _needs_rehashing = false; 182 _the_table = new_table; 183 } 184 185 // Lookup a symbol in a bucket. 186 187 Symbol* SymbolTable::lookup_dynamic(int index, const char* name, 188 int len, unsigned int hash) { 189 int count = 0; 190 for (HashtableEntry<Symbol*, mtSymbol>* e = bucket(index); e != NULL; e = e->next()) { 191 count++; // count all entries in this bucket, not just ones with same hash 192 if (e->hash() == hash) { 193 Symbol* sym = e->literal(); 194 if (sym->equals(name, len)) { 195 // something is referencing this symbol now. 196 sym->increment_refcount(); 197 return sym; 198 } 199 } 200 } 201 // If the bucket size is too deep check if this hash code is insufficient. 202 if (count >= rehash_count && !needs_rehashing()) { 203 _needs_rehashing = check_rehash_table(count); 204 } 205 return NULL; 206 } 207 208 Symbol* SymbolTable::lookup_shared(const char* name, 209 int len, unsigned int hash) { 210 if (use_alternate_hashcode()) { 211 // hash_code parameter may use alternate hashing algorithm but the shared table 212 // always uses the same original hash code. 213 hash = hash_shared_symbol(name, len); 214 } 215 return _shared_table.lookup(name, hash, len); 216 } 217 218 Symbol* SymbolTable::lookup(int index, const char* name, 219 int len, unsigned int hash) { 220 Symbol* sym; 221 if (_lookup_shared_first) { 222 sym = lookup_shared(name, len, hash); 223 if (sym != NULL) { 224 return sym; 225 } 226 _lookup_shared_first = false; 227 return lookup_dynamic(index, name, len, hash); 228 } else { 229 sym = lookup_dynamic(index, name, len, hash); 230 if (sym != NULL) { 231 return sym; 232 } 233 sym = lookup_shared(name, len, hash); 234 if (sym != NULL) { 235 _lookup_shared_first = true; 236 } 237 return sym; 238 } 239 } 240 241 u4 SymbolTable::encode_shared(Symbol* sym) { 242 assert(DumpSharedSpaces, "called only during dump time"); 243 uintx base_address = uintx(MetaspaceShared::shared_rs()->base()); 244 uintx offset = uintx(sym) - base_address; 245 assert(offset < 0x7fffffff, "sanity"); 246 return u4(offset); 247 } 248 249 Symbol* SymbolTable::decode_shared(u4 offset) { 250 assert(!DumpSharedSpaces, "called only during runtime"); 251 uintx base_address = _shared_table.base_address(); 252 Symbol* sym = (Symbol*)(base_address + offset); 253 254 #ifndef PRODUCT 255 const char* s = (const char*)sym->bytes(); 256 int len = sym->utf8_length(); 257 unsigned int hash = hash_symbol(s, len); 258 assert(sym == lookup_shared(s, len, hash), "must be shared symbol"); 259 #endif 260 261 return sym; 262 } 263 264 // Pick hashing algorithm. 265 unsigned int SymbolTable::hash_symbol(const char* s, int len) { 266 return use_alternate_hashcode() ? 267 AltHashing::murmur3_32(seed(), (const jbyte*)s, len) : 268 java_lang_String::hash_code((const jbyte*)s, len); 269 } 270 271 unsigned int SymbolTable::hash_shared_symbol(const char* s, int len) { 272 return java_lang_String::hash_code((const jbyte*)s, len); 273 } 274 275 276 // We take care not to be blocking while holding the 277 // SymbolTable_lock. Otherwise, the system might deadlock, since the 278 // symboltable is used during compilation (VM_thread) The lock free 279 // synchronization is simplified by the fact that we do not delete 280 // entries in the symbol table during normal execution (only during 281 // safepoints). 282 283 Symbol* SymbolTable::lookup(const char* name, int len, TRAPS) { 284 unsigned int hashValue = hash_symbol(name, len); 285 int index = the_table()->hash_to_index(hashValue); 286 287 Symbol* s = the_table()->lookup(index, name, len, hashValue); 288 289 // Found 290 if (s != NULL) return s; 291 292 // Grab SymbolTable_lock first. 293 MutexLocker ml(SymbolTable_lock, THREAD); 294 295 // Otherwise, add to symbol to table 296 return the_table()->basic_add(index, (u1*)name, len, hashValue, true, THREAD); 297 } 298 299 Symbol* SymbolTable::lookup(const Symbol* sym, int begin, int end, TRAPS) { 300 char* buffer; 301 int index, len; 302 unsigned int hashValue; 303 char* name; 304 { 305 debug_only(NoSafepointVerifier nsv;) 306 307 name = (char*)sym->base() + begin; 308 len = end - begin; 309 hashValue = hash_symbol(name, len); 310 index = the_table()->hash_to_index(hashValue); 311 Symbol* s = the_table()->lookup(index, name, len, hashValue); 312 313 // Found 314 if (s != NULL) return s; 315 } 316 317 // Otherwise, add to symbol to table. Copy to a C string first. 318 char stack_buf[128]; 319 ResourceMark rm(THREAD); 320 if (len <= 128) { 321 buffer = stack_buf; 322 } else { 323 buffer = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len); 324 } 325 for (int i=0; i<len; i++) { 326 buffer[i] = name[i]; 327 } 328 // Make sure there is no safepoint in the code above since name can't move. 329 // We can't include the code in NoSafepointVerifier because of the 330 // ResourceMark. 331 332 // Grab SymbolTable_lock first. 333 MutexLocker ml(SymbolTable_lock, THREAD); 334 335 return the_table()->basic_add(index, (u1*)buffer, len, hashValue, true, THREAD); 336 } 337 338 Symbol* SymbolTable::lookup_only(const char* name, int len, 339 unsigned int& hash) { 340 hash = hash_symbol(name, len); 341 int index = the_table()->hash_to_index(hash); 342 343 Symbol* s = the_table()->lookup(index, name, len, hash); 344 return s; 345 } 346 347 // Look up the address of the literal in the SymbolTable for this Symbol* 348 // Do not create any new symbols 349 // Do not increment the reference count to keep this alive 350 Symbol** SymbolTable::lookup_symbol_addr(Symbol* sym){ 351 unsigned int hash = hash_symbol((char*)sym->bytes(), sym->utf8_length()); 352 int index = the_table()->hash_to_index(hash); 353 354 for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(index); e != NULL; e = e->next()) { 355 if (e->hash() == hash) { 356 Symbol* literal_sym = e->literal(); 357 if (sym == literal_sym) { 358 return e->literal_addr(); 359 } 360 } 361 } 362 return NULL; 363 } 364 365 // Suggestion: Push unicode-based lookup all the way into the hashing 366 // and probing logic, so there is no need for convert_to_utf8 until 367 // an actual new Symbol* is created. 368 Symbol* SymbolTable::lookup_unicode(const jchar* name, int utf16_length, TRAPS) { 369 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); 370 char stack_buf[128]; 371 if (utf8_length < (int) sizeof(stack_buf)) { 372 char* chars = stack_buf; 373 UNICODE::convert_to_utf8(name, utf16_length, chars); 374 return lookup(chars, utf8_length, THREAD); 375 } else { 376 ResourceMark rm(THREAD); 377 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; 378 UNICODE::convert_to_utf8(name, utf16_length, chars); 379 return lookup(chars, utf8_length, THREAD); 380 } 381 } 382 383 Symbol* SymbolTable::lookup_only_unicode(const jchar* name, int utf16_length, 384 unsigned int& hash) { 385 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); 386 char stack_buf[128]; 387 if (utf8_length < (int) sizeof(stack_buf)) { 388 char* chars = stack_buf; 389 UNICODE::convert_to_utf8(name, utf16_length, chars); 390 return lookup_only(chars, utf8_length, hash); 391 } else { 392 ResourceMark rm; 393 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; 394 UNICODE::convert_to_utf8(name, utf16_length, chars); 395 return lookup_only(chars, utf8_length, hash); 396 } 397 } 398 399 void SymbolTable::add(ClassLoaderData* loader_data, const constantPoolHandle& cp, 400 int names_count, 401 const char** names, int* lengths, int* cp_indices, 402 unsigned int* hashValues, TRAPS) { 403 // Grab SymbolTable_lock first. 404 MutexLocker ml(SymbolTable_lock, THREAD); 405 406 SymbolTable* table = the_table(); 407 bool added = table->basic_add(loader_data, cp, names_count, names, lengths, 408 cp_indices, hashValues, CHECK); 409 if (!added) { 410 // do it the hard way 411 for (int i=0; i<names_count; i++) { 412 int index = table->hash_to_index(hashValues[i]); 413 bool c_heap = !loader_data->is_the_null_class_loader_data(); 414 Symbol* sym = table->basic_add(index, (u1*)names[i], lengths[i], hashValues[i], c_heap, CHECK); 415 cp->symbol_at_put(cp_indices[i], sym); 416 } 417 } 418 } 419 420 Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) { 421 unsigned int hash; 422 Symbol* result = SymbolTable::lookup_only((char*)name, (int)strlen(name), hash); 423 if (result != NULL) { 424 return result; 425 } 426 // Grab SymbolTable_lock first. 427 MutexLocker ml(SymbolTable_lock, THREAD); 428 429 SymbolTable* table = the_table(); 430 int index = table->hash_to_index(hash); 431 return table->basic_add(index, (u1*)name, (int)strlen(name), hash, false, THREAD); 432 } 433 434 Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len, 435 unsigned int hashValue_arg, bool c_heap, TRAPS) { 436 assert(!Universe::heap()->is_in_reserved(name), 437 "proposed name of symbol must be stable"); 438 439 // Don't allow symbols to be created which cannot fit in a Symbol*. 440 if (len > Symbol::max_length()) { 441 THROW_MSG_0(vmSymbols::java_lang_InternalError(), 442 "name is too long to represent"); 443 } 444 445 // Cannot hit a safepoint in this function because the "this" pointer can move. 446 NoSafepointVerifier nsv; 447 448 // Check if the symbol table has been rehashed, if so, need to recalculate 449 // the hash value and index. 450 unsigned int hashValue; 451 int index; 452 if (use_alternate_hashcode()) { 453 hashValue = hash_symbol((const char*)name, len); 454 index = hash_to_index(hashValue); 455 } else { 456 hashValue = hashValue_arg; 457 index = index_arg; 458 } 459 460 // Since look-up was done lock-free, we need to check if another 461 // thread beat us in the race to insert the symbol. 462 Symbol* test = lookup(index, (char*)name, len, hashValue); 463 if (test != NULL) { 464 // A race occurred and another thread introduced the symbol. 465 assert(test->refcount() != 0, "lookup should have incremented the count"); 466 return test; 467 } 468 469 // Create a new symbol. 470 Symbol* sym = allocate_symbol(name, len, c_heap, CHECK_NULL); 471 assert(sym->equals((char*)name, len), "symbol must be properly initialized"); 472 473 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); 474 add_entry(index, entry); 475 return sym; 476 } 477 478 // This version of basic_add adds symbols in batch from the constant pool 479 // parsing. 480 bool SymbolTable::basic_add(ClassLoaderData* loader_data, const constantPoolHandle& cp, 481 int names_count, 482 const char** names, int* lengths, 483 int* cp_indices, unsigned int* hashValues, 484 TRAPS) { 485 486 // Check symbol names are not too long. If any are too long, don't add any. 487 for (int i = 0; i< names_count; i++) { 488 if (lengths[i] > Symbol::max_length()) { 489 THROW_MSG_0(vmSymbols::java_lang_InternalError(), 490 "name is too long to represent"); 491 } 492 } 493 494 // Cannot hit a safepoint in this function because the "this" pointer can move. 495 NoSafepointVerifier nsv; 496 497 for (int i=0; i<names_count; i++) { 498 // Check if the symbol table has been rehashed, if so, need to recalculate 499 // the hash value. 500 unsigned int hashValue; 501 if (use_alternate_hashcode()) { 502 hashValue = hash_symbol(names[i], lengths[i]); 503 } else { 504 hashValue = hashValues[i]; 505 } 506 // Since look-up was done lock-free, we need to check if another 507 // thread beat us in the race to insert the symbol. 508 int index = hash_to_index(hashValue); 509 Symbol* test = lookup(index, names[i], lengths[i], hashValue); 510 if (test != NULL) { 511 // A race occurred and another thread introduced the symbol, this one 512 // will be dropped and collected. Use test instead. 513 cp->symbol_at_put(cp_indices[i], test); 514 assert(test->refcount() != 0, "lookup should have incremented the count"); 515 } else { 516 // Create a new symbol. The null class loader is never unloaded so these 517 // are allocated specially in a permanent arena. 518 bool c_heap = !loader_data->is_the_null_class_loader_data(); 519 Symbol* sym = allocate_symbol((const u1*)names[i], lengths[i], c_heap, CHECK_(false)); 520 assert(sym->equals(names[i], lengths[i]), "symbol must be properly initialized"); // why wouldn't it be??? 521 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); 522 add_entry(index, entry); 523 cp->symbol_at_put(cp_indices[i], sym); 524 } 525 } 526 return true; 527 } 528 529 530 void SymbolTable::verify() { 531 for (int i = 0; i < the_table()->table_size(); ++i) { 532 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); 533 for ( ; p != NULL; p = p->next()) { 534 Symbol* s = (Symbol*)(p->literal()); 535 guarantee(s != NULL, "symbol is NULL"); 536 unsigned int h = hash_symbol((char*)s->bytes(), s->utf8_length()); 537 guarantee(p->hash() == h, "broken hash in symbol table entry"); 538 guarantee(the_table()->hash_to_index(h) == i, 539 "wrong index in symbol table"); 540 } 541 } 542 } 543 544 void SymbolTable::dump(outputStream* st, bool verbose) { 545 if (!verbose) { 546 the_table()->dump_table(st, "SymbolTable"); 547 } else { 548 st->print_cr("VERSION: 1.0"); 549 for (int i = 0; i < the_table()->table_size(); ++i) { 550 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); 551 for ( ; p != NULL; p = p->next()) { 552 Symbol* s = (Symbol*)(p->literal()); 553 const char* utf8_string = (const char*)s->bytes(); 554 int utf8_length = s->utf8_length(); 555 st->print("%d %d: ", utf8_length, s->refcount()); 556 HashtableTextDump::put_utf8(st, utf8_string, utf8_length); 557 st->cr(); 558 } 559 } 560 } 561 } 562 563 void SymbolTable::serialize(SerializeClosure* soc) { 564 #if INCLUDE_CDS 565 _shared_table.reset(); 566 if (soc->writing()) { 567 int num_buckets = the_table()->number_of_entries() / 568 SharedSymbolTableBucketSize; 569 CompactSymbolTableWriter writer(num_buckets, 570 &MetaspaceShared::stats()->symbol); 571 for (int i = 0; i < the_table()->table_size(); ++i) { 572 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); 573 for ( ; p != NULL; p = p->next()) { 574 Symbol* s = (Symbol*)(p->literal()); 575 unsigned int fixed_hash = hash_shared_symbol((char*)s->bytes(), s->utf8_length()); 576 assert(fixed_hash == p->hash(), "must not rehash during dumping"); 577 writer.add(fixed_hash, s); 578 } 579 } 580 581 writer.dump(&_shared_table); 582 } 583 584 _shared_table.set_type(CompactHashtable<Symbol*, char>::_symbol_table); 585 _shared_table.serialize(soc); 586 587 if (soc->writing()) { 588 // Verify table is correct 589 Symbol* sym = vmSymbols::java_lang_Object(); 590 const char* name = (const char*)sym->bytes(); 591 int len = sym->utf8_length(); 592 unsigned int hash = hash_symbol(name, len); 593 assert(sym == _shared_table.lookup(name, hash, len), "sanity"); 594 595 // Sanity. Make sure we don't use the shared table at dump time 596 _shared_table.reset(); 597 } 598 #endif 599 } 600 601 //--------------------------------------------------------------------------- 602 // Non-product code 603 604 #ifndef PRODUCT 605 606 void SymbolTable::print_histogram() { 607 MutexLocker ml(SymbolTable_lock); 608 const int results_length = 100; 609 int counts[results_length]; 610 int sizes[results_length]; 611 int i,j; 612 613 // initialize results to zero 614 for (j = 0; j < results_length; j++) { 615 counts[j] = 0; 616 sizes[j] = 0; 617 } 618 619 int total_size = 0; 620 int total_count = 0; 621 int total_length = 0; 622 int max_length = 0; 623 int out_of_range_count = 0; 624 int out_of_range_size = 0; 625 for (i = 0; i < the_table()->table_size(); i++) { 626 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); 627 for ( ; p != NULL; p = p->next()) { 628 int size = p->literal()->size(); 629 int len = p->literal()->utf8_length(); 630 if (len < results_length) { 631 counts[len]++; 632 sizes[len] += size; 633 } else { 634 out_of_range_count++; 635 out_of_range_size += size; 636 } 637 total_count++; 638 total_size += size; 639 total_length += len; 640 max_length = MAX2(max_length, len); 641 } 642 } 643 tty->print_cr("Symbol Table Histogram:"); 644 tty->print_cr(" Total number of symbols %7d", total_count); 645 tty->print_cr(" Total size in memory %7dK", 646 (total_size*wordSize)/1024); 647 tty->print_cr(" Total counted %7d", _symbols_counted); 648 tty->print_cr(" Total removed %7d", _symbols_removed); 649 if (_symbols_counted > 0) { 650 tty->print_cr(" Percent removed %3.2f", 651 ((float)_symbols_removed/(float)_symbols_counted)* 100); 652 } 653 tty->print_cr(" Reference counts %7d", Symbol::_total_count); 654 tty->print_cr(" Symbol arena used " SIZE_FORMAT_W(7) "K", arena()->used()/1024); 655 tty->print_cr(" Symbol arena size " SIZE_FORMAT_W(7) "K", arena()->size_in_bytes()/1024); 656 tty->print_cr(" Total symbol length %7d", total_length); 657 tty->print_cr(" Maximum symbol length %7d", max_length); 658 tty->print_cr(" Average symbol length %7.2f", ((float) total_length / (float) total_count)); 659 tty->print_cr(" Symbol length histogram:"); 660 tty->print_cr(" %6s %10s %10s", "Length", "#Symbols", "Size"); 661 for (i = 0; i < results_length; i++) { 662 if (counts[i] > 0) { 663 tty->print_cr(" %6d %10d %10dK", i, counts[i], (sizes[i]*wordSize)/1024); 664 } 665 } 666 tty->print_cr(" >=%6d %10d %10dK\n", results_length, 667 out_of_range_count, (out_of_range_size*wordSize)/1024); 668 } 669 670 void SymbolTable::print() { 671 for (int i = 0; i < the_table()->table_size(); ++i) { 672 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); 673 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); 674 if (entry != NULL) { 675 while (entry != NULL) { 676 tty->print(PTR_FORMAT " ", p2i(entry->literal())); 677 entry->literal()->print(); 678 tty->print(" %d", entry->literal()->refcount()); 679 p = entry->next_addr(); 680 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); 681 } 682 tty->cr(); 683 } 684 } 685 } 686 #endif // PRODUCT 687 688 689 // Utility for dumping symbols 690 SymboltableDCmd::SymboltableDCmd(outputStream* output, bool heap) : 691 DCmdWithParser(output, heap), 692 _verbose("-verbose", "Dump the content of each symbol in the table", 693 "BOOLEAN", false, "false") { 694 _dcmdparser.add_dcmd_option(&_verbose); 695 } 696 697 void SymboltableDCmd::execute(DCmdSource source, TRAPS) { 698 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSymbols, 699 _verbose.value()); 700 VMThread::execute(&dumper); 701 } 702 703 int SymboltableDCmd::num_arguments() { 704 ResourceMark rm; 705 SymboltableDCmd* dcmd = new SymboltableDCmd(NULL, false); 706 if (dcmd != NULL) { 707 DCmdMark mark(dcmd); 708 return dcmd->_dcmdparser.num_arguments(); 709 } else { 710 return 0; 711 } 712 }